SUCCESS in the breeding game boils down to choosing the right man for the job, writes STUART BARBER

When you decide to buy a bull, or a ram, a buck, a rooster or any male to mate with female, you need know how to select the best animal for the job.

The first thing to ensure is that the male is capable of the reproductive task you are about to set him. Are your expectations of how many females he can mate realistic?

Also, is he able to carry out a "normal" mating load? An acceptable mating load for a bull might be anywhere between 10 and 80 cows, although an average is closer to 35. There is a large variation between individual bulls and it's important to know where you stand.

You should consult a vet on the best methods of assessing the fertility of your particular male prior to mating. If the male is unable to mate, it doesn't matter how good a "sire" he should or could be, he won't contribute his genetics to the next generation.

The second thing to consider is what influence you want the male to have on his progeny. If you want to breed the next winner of a show based primarily on looks, then you should consider appearance in your selection process. If you are more interested in commercial productivity, then you consider a genetic-analysis program incorporating relevant breed traits.

Many farm managers will integrate both ideals to produce a good looking, functional animal. The choice is up to you, although you should always consider animal welfare, so avoid joining animals that are likely to result in problems during birth or ill health.

Selection of animals using visual appearance is a time-honoured method of breeding "like" with "like" to produce an animal of similar or better appearance. Alternatively, you can try to introduce new visual traits by breeding animals of different appearance.

Often this will be done to create a particular breed type. The success of this method will vary depending on how "heritable" these traits are - how likely it is these traits are passed from one generation to the next.

The other main method of selection is using objective information such as weight gain, wool micron, milk yield or other criteria that can be measured accurately and objectively.

Today's technology allows breeders to compare genetic traits such as how many lambs a ewe might feed, or the date she lambed or had her lambs weaned. Known by the awkward title "best linear unbiased predictor" technology, or BLUP, this is a method of comparing objective genetics without considering environmental effects.

Information about the animal's particular traits are entered into a computer program which then rates the animal. These BLUP analyses are available for a number of industries including beef, where it is known as Breedplan. Information on an individual animal's traits such as weight, carcass and fertility are entered and the animals is then given an estimated breeding value, or EBV. The calculation also includes information on the animal's relatives, the heritability of each trait and the relationship between the traits.

Although these ratings say nothing about how reproductively sound a particular animal is, they are an excellent way of assessing the probable genetic potential of an animal and allow a breeder to compare different animals.

In coming years, these BLUP analyses may also have genomic data added to the values as research is currently being done in this field.

With any breeding program, always make sure you start with animals that are structurally and reproductively sound - they must walk well and be able to mate easily. You then need to work out what method of selection you wish to follow and educate yourself to maximise its benefits.

Then regularly review what your selection program has achieved.

You should be able to see a 10 per cent improvement in your animals over five years if your program is successful.

  • Dr Stuart Barber is a lecturer in veterinary science at the University of Melbourne.